Electric condenser



Feb. 3. 1 925.

R. KNOPP ELECTRIC CONDENSER Filed June 19, 1922 2 Sheets-Sheet 1 Feb. 3. 1925. 1,525,302

R. KNOPP ELECTRIC CONDENSER Filed June 19, 1922 2 Sheets-Sheet 2 Patented Feb. 3, 1925.

UNITED STATES PATENT OFFICE.

RUDOLPH KNOPP, F CEDAR GROVE, NEW JERSEY, ASSIGNOR T0 FRANK J. QUIGAN, INCL, OF BROOKLYN, NEW YORK, A FIRM OF NEW YORK.

ELECTRIC CONDENSER.

Application filed June 19, 1922. Serial No. 569,364.

To all whom it may concern:

Be it known that I, RUDOLPH Knorr, a citizen of Czechoslovakia, and aresident of Cedar Grove, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Electric Condensers, of which the following is a spec1fication.

This invention relates to an electric condenser and more particulary, to a variable capacity condenser for use in connection with radio telegraphic and telephonic apparatus.

It is the primary object and purpose of my present improvement to provide an electric condenser of simple and compact construction but of relatively great capacity and which is capable of a very fine adjustment, thus affording greater selectivity in tuning between the receiving and sending station.

In one embodiment of my present invention, I provide opposed condenser plates between which a suitable dielectric is interposed and cam means for moving one of said plates relative to the other whereby a general adjustment of the capacity may be obtained. In conjunction with said condenser lates, I provide a second independently adustable plate which maybe positioned with relation to a fixed plate in electrical connection with the fixed condenser plate whereby a further and finer adjustment of the capacity may be obtained.

It is also a further general object of the 5 invention to provide an electric condenser of small size for use in connection with portable wireless apparatus and in which the several arts are so constructed and arranged t at they may be easily and quickly 4o disassembled for the purpose of adjustment and repair without requiring the services of a skilled electrician.

With the above and other objects in view, the invention consists in the improved electric condenser and in the form, construction and relative arrangement of its several parts as will be hereinafter more fully described, illustrated in the accompanying drawings and subsequently incorporated in the subjoined claims.

In the drawings wherein I have shown one practical and satisfactory embodiment of the invention and in which similar reference characters designate corresponding parts throughout the several views.

.ment of the invention I provide a bod and in particular, apparatus employed in wireless telephonic communication, it has been found that with the several types of condensers at present in use, it is fr uently not possible to obtain the necessar neness in adjustment or variation of t e micra farad capacity in order to secure accurate tuning between the sending and receivin stations, I aim to overcome this difficulty by combining in a single instrument, primary and secondary independently adjustable condensing means whereby it is possible to secure a very minute variation in the capacity between the maximum and minimum,

say from .001 micra farad to almost zero.

As herein shown, in a preferred embodiplate 5 of hard rubber or other suitable insulating material which is fixed at one of its ends to a base 6. Upon one side of the plate 5 one end wall 7 of a housing or casing for the movable parts of the condenser is arranged, said wall having an ofiset annular marginal flange 8 which is suitabl secured to the insulation plate 5. The b0 y 9 of the housing or casing, which is preferably of cylindrical form, has its annular wall seated against the end wall 7 and is rigidly secured 1n fixed relation to said end wall by a series of tie-bolts 10. The end wall of the body-9 has a portion thereof pressed inwardly as indicated at 11, said inwardly pressed wall portion extending through substantially 180.

In a bearing 12 of insulating material centrally fixed in the end wall of the casin body 9, one end of a shaft 13 is rotatably supported. This shaft extends through a sleeve 14 which is loosely mounted in the insulation plate 5, one end of said sleeve being supported in a bearing collar 15 of insulating material which is fixed in an outno wardly projected central portion 16 of the end wall 7. This sleeve terminates in an .annular flange 17 engaged with the inner side of the collar 15 and is formed with a cam surface 18.

The movable condenser plate 19 is axially shiftable upon the shaft 13 and is provided with a complementary cam face 20 with which the cam face 18 on the end of the sleeve 14 coacts. Between this movable plate 19 and the end wall 7 which constitutes the fixed condenser plate, a sheet of mica or other suitable dielectric 21 is interposed. The dielectric may either be secure-d to the face of the wall 7 or it may be fixed upon the opposed face of the movable condenser plate 19. A coil spring 22 yieldingly urges the movable plate 19 towards the fixed I condenser plate 7 and maintains the cam surfaces 20 and 18 in contacting relation. At diametrically opposite points the edge of the movable condenser plate 19 is notched as at 23 to receive the tie-bolts 10 and atone of these notches a mica strip 24 is fixed to said plate and is also providedwith a notch 25 to closely receive one of the tiebolts 10. The axially shiftable condenser plate is thus held against, a. rotatiye movement and also insulated from electrical connection to the fixed plate 7.

A suitable knob 26 is fixed upon the outer end of the sleeve 14 and carries an index finger or pointer 27 for movement over a suitable scale 28 which may be calibrated in units of capacity or may be simply marked off in arbitrary divisions, as shown in Figure 1 of the drawings.

Upon the shaft 13 within the housing or casing a collar 29 is fixed by means of the set-screw 20 and to one end of said collar a plate 31 is fixed, said plate being disposed closely adjacent. to the inwardly projected section 11 of the end wall of the housing and having planetary movement in a parallel plane. An arm 32 of insulating material is arranged between the collar 29 and one end of the spring 22 and at its outer end is notched as at 33 to receive one of the tie-bolts 10. Upon the other end of the shaft 13 a suitable operating knob 34 is fixed whereby a rotary movement may be imparted to the condenser plate 31 independently of the shifting movement of the condenser plate 19 and said plate 31 thereby positioned with respect to the inwardly projected section 11 of the end wall of the housing. It will be understood that the plate 31 also has a circumferential extent of 180 and by adjusting said plate, a greater or less extent thereof may be positioned in opposed relation. to the. wall section 11.

Suitable terminals are provided for the circuit wires, said terminals being herein illustrated by the binding posts 35 and 36. The binding post 35 is insulated from the micra farad to approximately zero.

metal wall of the housing or casing by the insulating block 37 anu is connected by the copper conducting strip 38 with the movable condenser plates 19 and 31 through the shaft 13. The other binding post 36 is in direct electricalconnection with the metal body wall of the housing and through said wall with the fixed condenser plate 7.

From the foregoing description considered in connection with the accompanying drawings the operation of the condenser will be readily understood by those skilled in the art. A general adjustment of the capacity mav be easily and quickly secured by rotating the sleeve 14 through the medium of the knob 26, the position of the pointer or index inen'iber 2711s it moves over thescale 28 being noted. In the rotation of further and finer adjustment of the capacity to secure'more accurate and sensitive tuning,

the operator now turns the knob 34 to thereby move the secondary condenser plate 31 in a rotary path and change its position relative to the inwardly struck section 11 of the housing wall. In this adjustment, it is understood that the primary condenser plate 19 is maintained in the position to which it has been moved with respect to the fixed plate 7. Thus it will be readily seen that it is possible to secure a very fine variation in the capacity of the condenser. The coacting cam elements 18 and 20 are so formed that in the rotation of the sleeve 14 through 180, the shiftablc condenser plate will be moved so as to change the capacity from .%01

etween these extremes various capacities may be secured by the proper positioning of the index or pointer 27 on the scale 28, and a further and finer adjustment can be obtained by the planetary movement of the secondary ing from the principle involved. It is accordingly to be understood that while I have herein disclosed a satisfactory and practical embodiment of the device, it may be constructed in various alternative forms without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In an electric condenser, a metal casing having an inwardly struck wall Section coustituting a fixed condenser member, a sec-- ond metal condenser member rotatably supported within said casing, and means for adjustably positioning said rotatable condenser member relative to the fixed condenser member.

2. In an electric condenser, stationary and movable condenser plates, a shaft supporting the movable plate, and manually operable coacting cam parts for shifting the movable plate axially of said shaft.

3. In an electric condenser, a stationary condenser plate, a non-rotatable con-denser plate opposed to said stationary plate and provided with a cam part, and a rotatably mounted manually operable cam part coacting with the cam part on said condenser plate to adjustably space said electric condenser plate from the fixed plate.

4. In an electric condenser, a fixed condenser plate, a non-rotatable condenser plate opposed to said fixed plate and provided with a cam part, a spring normally urging said non-rotatable plate towards the fixed plate, a dielectric interposed between the opposed surfaces of said plates, and a manually rotatable cam part coacting with the cam part on said condenser plate to shift the same against the action of said spring and vary the space between one of said plates and the dielectric.

5. In an electric condenser, primary and secondary capacity adjusting means, said primary means including a non-rotatable axiall shittable condenser plate, and said secon ary means including a rotatable condenser plate, and manually operable means for independently adjusting said movable condenser plates.

6. In an electric condenser, primary and secondary capacity adjusting means, said primary means including a non-rotatable axially shii'table condenser plate, and said secondary means including a rotatable condenser plate, coacting cam parts for shifting said primary condenser plate, and independently operable means for imparting a rotary movement to the secondary condenser plate.

7. In an electric condenser, a casing having opposite side walls constituting fixed condenser members, two movable condenser members mounted within the casing in opposed relation to the respective fixed condenser members, means for imparting a rotary movement to one of the movable condenser members to position the same with relation to the opposed fixed condenser memher, and additional means for imparting an independent lateral bodily movement to the other movable condenser member towards or away from the other fixed condenser member.

In testimony that I claim the foregoing as my invention, I have signed my name hereunder.

RUDOLPH KN OPP. 

